This invention relates to moulding compositions for the manufacture of shaped articles, and is primarily concerned with providing a novel composition from which fire-resistant shaped articles may be made. The invention also relates to a method for making the shaped articles and to the shaped articles themselves.
The shaped articles with which I am especially concerned in this invention are those whose application requires them to exhibit a degree of fire-resistance and high temperatureresistance. Thus I am particularly concerned with the manufacture of building boards, for use both in the building and shipbuilding industries, where good fire-resistance is important; I am also concerned with products whose use exposes them to high temperatures, and in this category may be mentioned components of ovens, e.g. walls and door linings, and metal, e.g. aluminium, casting equipment.
It is well known to make building boards, and other shaped articles useful in the building, shipbuilding and metal casting industries, from compositions containing binders and reinforcing fillers. Suitable binders for this purpose include Portland cement and the family of binders known as the "calcium silicates", which latter are made by the reaction, under autoclaving conditions, of a calcareous component (which might be Portland cement) and a siliceous component. Typical fillers for such compositions are asbestos fibres, which are most useful in providing the ultimate products with strength, heat resistance and fire resistance, and asbestos-cement and asbestos-calcium silicate products have found much favour throughout the world for a wide variety of applications.
However, the use at the present time of asbestos is thought to create a health hazard, and there is thus urgently sought non-asbestos products which possess all the advantages of asbestos-reinforced products but at the same time do not involve their disadvantages. It is thus an object of the present invention to provide an asbestos-free composition from which boards and other shaped articles may be manufactured.